Mariner s compass



UNITED STATES PATENT FFICE.

EDWARD SAMUEL RITCHIE, OF NEWTON, MASSACHUSETTS.

MARI N ERS COM PASS.

SPECIFICATION forming part of Letters Patent No. 503,164, dated August15, 1893.

Application filed January 16, 1893. Serial No. 458,476. (No model.)

. noted, and that the force required may be apev plied and transmittedto the inside of the compass bowl without causing any of the inclosedliquid to escape, or the admission of any bubbles of air within thebowl; which Iv attain by the mechanism described in the specificationand represented in the accompanying drawings of which-h Y Figure 1 is abottom View ofv the compass bowl, the cover being removed. Fig. 2 is avertical transverse'section. Fig. 3 is a top View of a section on theline x on Fig. 2.

Similar letters refer to similar parts in the several views.

In the drawings A, denotes the compass bowl of brass or other suitablemetal; B, the top ring; C, a glass cover; D, movable cover below thebowl; E, the compass card bearing the usual cardinal divisions, magneticneedle, and central cap to rest upon the supporting pivot a, which isattached to the bar b, extending across the bowl.

The bottom c, of the bowl A, has a hole, or an opening, covering whichis a thin flexible metal plate d, having its outer edge raised so thatit can be soldered firmly to the bottom plate c, of the bowl. Themiddleportion of the' plate d, is thus separated from, and is parallelwith the bottom plate o, so that its central portion can be raised, orbe depressed through its elasticity, without coming in contact with theplate c. The lever or arm e, has one end attached to the bowl A. Itsopposite end is turned up to come in contact with the lever t', which isattached by a hinge m, to the bowl A. The lever t', extends past thecenter of the bowl, and has an open slit, allowing its free 5o motionover the pivot a. A projection n, be-

low the lever e, extends through the opening in the bottom of the bowl,and comes in contact with the flexible plate d. The lever or arm o, isattached by a screw, or byahinge below the bottom of the bowl A. It isbent, and extends up on the outside of the bowl, and is again bent atright angles. Aprojection r, on the lever o, comes in contact with theiiexible plate d. The lever S is connected with the bowl A. by a hingeu. The portion surrounding the pin of the hinge u, is formed as a cam,on which rests the outer end of the lever o.

In operation, by depressing the lever S, its cam raises the lever o,which raises the center of the liexible plate d, and the interior levere, which presses up the lever t', bringing it into contact with the cardE, raising it, and pressing it against the glass cover C, the card E,will thus be held in position until it is released by the raising of thelever S. To the bottom of the bowl is attached an expansion chamber w,of thin metal, to compensate for the change in volume'of the liquid withwhich the bowl is filled, by change in temperature. This is of usualconstruction.

It is evident-that any mechanical equivalent to the levers o, and S, maybe used to produce the external pressure on the plate d. I am aware thata lever has been employed to raise the card from the pivot in drycompasses; and also in liquid compasses, moved by a sliding rod orscrew. The objection to such has been the leakage of air, or liquid,around the sliding rod or screw.

It is evident that the projection, n, on the lever, e, and theprojection, fr, on the lever, o, may be made of one rod passing throughthe plate, d, and fastened to it air tight, so that it can be used inplace of the separate rods n,

and r. In practice I prefer to make it in this manner.. e

What I claim as my invention, and desire to secure by Letters Patent,is-

1. The combination in a compass of the card E, the lever z', the levere, the flexible plate d, and the lever o, substantially as described.

2. The combination in a compass of the card E, the pivot, a, the lever,i, the flexible plate, d, and the lever, 0 and connections between thelevers o and c', substantially as set forth.

IOO

3. The combination in a compass of the bowl A, the flexible plate, d,andthe expanbowl l?, the pivot a, the card E, the flexible sive chamber,w, substantially as set forth. plate c the lever o, with connections fortrausy 1 l Y mittng external pressure to the card E, and EDWARD SAMUELRm CHIE 5 the expansive chamber w, substantially as set Witnesses:

forth. A. M. RITCI-IIE,

4. -The combination in a compass of the R. C. WHITFORD.

